Disconnecting air-break switch



Dec. 3l, 1929. TI F JOHNSQN, JR I 1,742,144

DISCONNECTING AI'R BREAK SWITCH Dec. 31, 1929. T, F JOHNSON, JR 1,742,144

DISCONNECTING AIR BREAK SWITCH Filed Dec. 20, 1926 3 Sheets-Sheet 2 Ki* il? @zmlo' @manier/mami,

@Ofi/WOM@ l l Dec. 3'1, 1929.

T. F. JOHNsoN, JR 1,742,144

DISCONECTING AIR BREAK SWITCH Filed Deo. 20, 1926 Sheets-Sheet 3 Patented Dec. 3l, `1929 UNITED STATES PAT ENT OFFICE DrscoNNEcTNe 1n-BREAK swITcn Application med :December zo, 192e. serial 1ro. 156,009.

This invention relates to disconnecting air break switches for useon high tension transmission systems, and aimsamong other objects, to provide means for manually closing 5 the switch blade or blades and locking the blades in closed positions in combination with manual or automatic trip means at predetermined current values whereby the blade 0r blades are free to open..

vide an automatic air break, instantanepus, switch, adapted to be tripped at predetermined current values and having solenoid operated releasing mechanism, in combina.

tion with manually operable means to reset the switch, so arranged that it may be moved to a position where theswitch is free to open automatically, locked in closed position or manually opened, and, also, means to short circuit and to protect the solenoid against abnormal currents when the trip mechanism is actuated. Further, the invention contemplates mechanical connections between a plurality or gang of switches of this character so f arranged that the opening of one switch causes the opening of the others, independently of the manually operating mechanism and independently of each other as well as all in unison when they are manually tripped;

tion will appear in the specification when considered in connection. with the illustrative embodiment thereof shown in the accompanying drawings, wherein:

Figure 1 is a side elevation of the invention with parts broken away.

Figure 2 is an enlarged sectional view of the switch actuating mechanism.

Figure 3 is a horizontal Asection taken on the line 3--3 of Figure 2.

Figure 4 is a vertical section taken on the line 4-4 of Figure 2.

Figure 5 is a plan view of the means for connecting the several switches in a gang.

In actual practice the switches will usually be operated in a gang, the number corresponding to the conductors used in a transmission system. In the present example, each of these switches is mounted on a supi f porting member in the form of a bar 10. For

Another aim of the invention is to pro-'f' This supporting mem Other aims and advantaves of the inven-v this purpose, three insulators 11, 12 and 13 are mounted on the bar 10, and suitable supporting means such as brackets 14, 15 and 16 are secured tothe tops 'of the respective insulators. The middle insulator 12 is secured on a. pin 17, which is rotatably mounted for a purpose hereinafter explained and the insulation 11 and 13 are stationary.

The switch blade 18 is shown as being mounted on a pivot pin 19, between two arms 20 of a bifurcated su porting member 21.

ber is secured at its rear end to the bracket 14, and at its front end, its arms 20 are connected by a web 22, which rests on the bracket 15 and is retained thereon by a pivot pin 23 secured in the upper face of the bracket. The blade 18 cooperates with a pair of jaws 24, which are ,preferably constructed as shown in my co-pending application, Serial No. 139,459, iled October 4,v 1926, although the application of the present invention is not necessarily limited there-` to.

On the support or bracket 15 is mounted -blade operating means,fherein, inthe form of a cam 25, which is adapted to cooperate with a heel 26 on the switch blade, and is so shaped that the rocking of the bracket 15 and insulator 12 in one direction, or the other, will serve to close or open the switch blade. To lock the switch blade closed a spring operated latch 27 is shown as being plvotally mounted bewhich is carried on an arm 29 extending downwardly and forwardly from the supporting member 21. The latch 27 in this instance hastwo arms 30, extending upwardly on opposite sides of thesupporting member 21 .and of the heel 26 of the switch blade. A pin or roller 31 connects the arms 30, and is .adaptedto engage a shoulder 32 formed on the heel of the switch blade to latch the latter when it is closed.

Herein, on each side of the supporting member 21 there isa bar-33, with one end pivotally connected, as at 34,-to the latch 27, and with its other end slidabl mounted in a lug 35, projecting laterally rom the rear end of the supporting member. Anfexpansile coil spring 36 surrounds the bar 33, and

Vneath the heel 26 of the blade on a pin 28,

the front end of the bar is threaded, as at 37,

to receive an adjusting nut 38, against which the front end of the spring bears so that the latch is held closed under more or less compression. Under normal conditions, therefore, for which the nut 38 is adjusted, the latch will `be held in 4engagement wit-h the heel of the switch blade to hold the latter closed. The heel is rounded or cut away to present a smooth cam surface 39 at its rear end, so that as the blade moves from open to closed position, this cam edge willengage the a shell 41, and is clamped in a bracket 42,

extending upwardly from the supporting member 21. The coil of the solenoid is wound on a brass sleeve or spool 43, in which a core j or plunger 44 is slidably mounted. This plunger preferably consists of a brass tube filled with soft iron wire for a portion of its length. A head 45 is slidably mounted. in the front end of the plunger 44, and is provided with a transverse pin 46 extending through longitudinal slots 47 in the sides of the plunger. The pin 46 also extends into slots 48 formed in' the upwardly extending arms 30 of the latch 27. ,The end of the head acts as a spring bumper for the blade when it swings open since the rear end of the plunger comprises the spring 68.

Under normal conditions, the current passes overv the conductor 49 to the bracket 16, and thence through cables 50, which connect the latter to the jaws 24. It passes thence through the switch blade 18 and cables 51, which connect the latter to the supporting member 21. From the supporting member, the current passes to a binding screw 52 at one end of the solenoidl 40, and thencethrough the solenoid coil and out at 53 to a bracket 54, which is clamped to the rear end of the sleeve 43, but is insulated therefrom by a cylindrical bushing 5 5. The current passes thence into the conductor 56, which is connected with the bracket 54. A metallic collar 57 is also secured to the rear end of the sleeve 43, and a screw 58, in the bracket 54, is adjusted to form a spark gap for protection against lightning or other abnormal disturbances. It will be seen, therefore, that when the switch is closed, the current normally passes through the -coil of the solenoid 40. The normal current, however, is not suicient to actuate the plunger 54, and the latch 27 normally remains in its foremost position, locking the blade closed. In the present example,

this position is determined by set screws 59 in the sides of the arms 30, which engage corresponding abutments formed on the sides of the member 21. Gages 60 are secured to the sides of the latch 27, adjacent the nut 38, to designate where the latter must adjusted, so that the solenoid will trip the latch when subjected to a predetermined current value, thereby releasing the switch blade and permitting it to open.

Mechanism is provided for automatically opening the switch blade whenever the latch 27 is tripped. For this purpose, the bracket 42 is provided with upwardly extending arms 61, in which a clip 62 is hinged.v Secured in this clip is a comparatively long tubular member 63, in which a rod 64 is mounted and operatively connected to the switch blade. The front end of this rod is pivotaly connected to the blade 18, and the rod is constantly urged rearwardly by an expansile coiled spring 65, which surrounds the same within the tubular member 63. The spring 65 isv under sutlicient compression to open the switch blade practically instantly whenever the latter is unlatched, and the rear end of the tubular member 63 is closed, so as to form an air cushion for the piston as the blade approaches open position.

In order to prevent the solenoid 40 from being damaged in case the switch blade should fail to open when tripped, or in case the arc formed when it opens is not extinguished immediately, provision is made for shunting the current past the solenoid coil as soon as the latch 27 has been retracted. For this purpose, the upper part of the bracket 54 has a rearwardly extending arm 66, in which is supported a pin or bolt 67 in alinement with the plunger 44. The pin 67 is slidably mounted in the end of the arm 66, but is normally projected toward the solenoid by a coil spring 68. As soon as the plunger has been actuated to retract the latch 27 therefore, the rear end of the plunger contacts with the head of the in 67, and the current is shunted through tlie plunger 44, pin 67, arm 66 and bracket 54 without passing through the coil.

In order that the opening of one switch will cause the opening of the other switches in the gang, each latch 27 is formed at its lower end, below the pivot' 28, with a lug 69, in which a rod 7 0A is slidably mounted. The front end of this rod is formed with a hook 71, which engages a perforated ear 72, formed on the bracket 15. The rear portion of the rod 70 is surrounded by an expansile coil spring 73, with one end of the sprin engaging an adjustable nut 74 on the end o the rod, and with the other end of the spring engaging a head 75, which is slidable on the rod and bears against the rear face of thelug 69;

In order to close the switch blade 18, the

insulator 12 and the supporting member or bracket are rocked to the position shown in-Figure 2 where the highest part of the camengages the heel 26 of the blade, and .5 as the blade closes, the pin or roller 31 rides over the inclined edge 39 and snaps beneath theY shoulder 32 to latch the blade in closed position.l The bracket `15 is then rocked in the opposite direction until the downwardly 10 and laterally inclined portion of the cam 25 is clear of and beneath the heel 26. This rearward movement of thel supporting member or bracket 15, however, is not continued farenough to compress lthe spring 73 to any 15 considerable extent, because to do so would cause the spring 73 to trip the latch 27. The cam 25, however, is in such a position that when the blade 18 opens, after being released through the action of the solenoid, the heel 23 26 is free to move until the blade is open an'd then strikes the inclined -face of the cam 25. As the switch blade continues to full o en position, the heel will ride along the sur ace of the cam, and will continue the retractive 55 movement of the supporting member or bracket 15. Since the supporting members or brackets 15, in-the several switchesV of the gang, are connected so as to operate in unison, the brackets 15 on the other bars l0 will be ,i3 rocked in like manner. I,Such a rocking movement will draw the respective rods 70 forwardly, and will compress the s rings 73 sufficiently to actuate the latches 27 on the other switches,and cause themall to be tripped.

33 The actuation of the latches 27, by means of the rods 70 and springs 73, is independent of the position of the solenoid plungers, since the slots 47 permit the latches to be tripped without actuating the plungers.

Any suitable means may be provided for connecting the middle insulators 12 of the gang. In `the form shown in Figures 1 and 5, each pin 17 has an arm `7 6 extending therefrom, and the extremities of the several arms 76 are connected by suitable links 77. In 0rder that the switches may be opened or closed manually and independently of the solenoids,

' one pin 17 of the gang has-a shaft 78 secured thereto, which is mounted at its lower end in 50 a base 79 on the ground, and is provided with a hand lever 80.

The switch above described may be manufactured at considerably less cost than oil switcheswhich are now'4 in pommon use, yet it is entirely practical and is reliable. The'core of the solenoid and the plunger rod are immediately responsive to changes in the current, andthe switch will be immediately tripped as soon as the current, passing uo through the same, reaches the abnormal amperage for which it has been set. The trip mechanism, in connection with the solenoid, i may, of course, be used on a single switch as well as in gangs.

While I have shown and described the invention in what appears to be its dpreferred form, it is obvious that various mo itcations may be made therein without any material departure from the essential features thereof as defined in the claims.

What is claimed is:

1. The combination with a switch blade and jaws cooperating therewith, of a solenoid coil through which the current normally passes, a plunger reciprocable within said coil, means actuated by the movement of the plunger, when subjected to a predetermined overload, to cause the switch blade to open, and means cooperatingwith the plunger for establishing a short circuit past the coil as soon as the plunger has been so moved, whereby to prevent injury to the coil in case the switch fails to open under such conditions.

2.' The combination with a switch blade and jaws cooperating therewith, of a solenoid including a plunger, and a coil through which the current normally passes and within which the plunger is reci rocable, means actuated by the movement ot the plunger, when the solenoid is subjected to a predetermined overload, to cause the switch blade to open, and means for shunting the current through the" plunger past the coil as soon as the plunger has been so moved, whereby to revent injury to the coil in case the switch ails to open under such conditions.

3. The combinationwith a switch blade, a

latch engageable with the blade as it is closed and normally preventing it from opening again, and means for opening said blade as soon as itis released by the latch, 'of a sclenoid having a coil through which the current normally passes, and-a plunger reciprocable within said coil, means actuated-by the movement of the plunger, when subjected to a predetermined overload, to retract said latch and release the blade, and means for establishing' a short circuit past the coil as soon as the plunger has been so moved, whereby to revent injury to the coil incase the switch ails to open under such conditions. y

4. The combination with a switch blade, of

-a solenoid` having a coil lthrough which the current normally passes and a plunger reciprocable within said coil, means actuated by the movement of the plunger` when subjected to a predetermined overload to cause the switch blade to open, brackets to which the solenoid is secured, said plunger and one of the brackets being electrically connected to the-switch blade and throughthe jaws' to one end` of the line, the other bracket being electrically connected to the other end of he line but insulated from the plunger, an arm on said last-menticied bracket, and means carried by said arm in the` path of the plunger to establish a. shunt through thev latter `and past the/coil as soon as the plunger is actuated bythe overload, wherebyto prevent injury to the coil in case the switch fails to open under such conditions.

- 5. The combination with a switch blade1 a latch engageable with the blade as it is closed and normally preventing it from opening again, and. means for opening said plunger as soon as it is released by the latch, of a solenoid having a coil through which the current normally passes, and a plunger reciprocable Within the coil, means actuated by the movement ot the plunger, when subjected to a predetermined overload` to retract said latch and release the blade, brackets in which the solenoid is mounted, said plunger and one of the brackets being electrically connected to the switch blade and through the jaws to one end of the line, the other bracket being electrically connected to the other end of the line but insulated from the plunger, an arm on said last-mentionedbracket, andmeans carried by said arm in the path of the plunger to establish a shunt through the latter as soon as it is actuated by the overload, whereby to prevent injury to the coil in case the switch fails to open under such conditions.

6. The combination with a switch blade, of asolenoid having a coil through which the current normally passes, a plunger reciprocable within the coil, lmeans actuated by the movement of the plunger when subjected to a predetermined overload to cause the switch blade to open, and manually operable means to actuate said first-mentioned means independently of the solenoid and without shifting said plunger.

7. The combination with a switch blade and jaws cooperating therewith, of a solenoid coil through which the current normally passes, a plunger reciprocable within said coil, means actuated by the movement of the plunger when subjected to a predetermined overload to cause the switch blade to open, means for establishing a short circuit past the coil as soon as the plunger has been so moved, wherebyto prevent injury to the coil in case the switch fails to open under such conditions, and manually operable means to actuate said irst-mentioned means independently `of the solenoid and without shifting said plunger.

8. The combination with a switch blade, a latch engageable with the blade as it is closed and normally preventing it from opening again, and means for opening said blade as soon as it is released by the latch, of a solenoid having a coil through which the current normally passes, and a plunger reciprocable y'within said coil, means actuated by the movei `ment of the plunger, when subjected to a predetermined overload,'to retract said latch and release the blade, means Jfor establishing a short circuit past the coil as soon as the plunger has been so moved, whereby to prevent injury to the coil in ycase the swltch fails to open under such conditions, and manually operable means to retract said latch independently of the solenoid and without shifting said plunger.

9. The combination with a switch blade, of a solenoid having a coil through which the current normally passes and aplunger reciprocable within said coil, means actuated by the movement of the plunger when subjected to a predetermined overload to cause the switch blade to open, brackets to which the solenoid is secured, said plunger and one of the brackets being electrically connected to the switch blade and through the jaws to one end of the line, the other bracket being electrically connected to the other end of the line but insulated from'the plunger, an arm on said last-mentioned bracket, means carried by said arm in the path of the plunger to establish a shunt through the latter and past the coil as soon as the plunger is acutated by the overload, whereby `to prevent injury to the coil in case the switch fails to open under such conditions, and manually operable means to actuate said irst-mentioned means independently of the solenoid and without shifting said plunger.

10. In a switch of the class described, the

combination of a supporting member, a blade pivotally mounted thereon and having a heel extending rearwardly of its pivot, a latch pivotally mounted on the supporting member and normally engaging under the heel of the blade, means automatically operable by a predetermined overload to retract said latch from beneath the blade, manually operable means for retracting the latch in a similar manner, and means for opening the' blade as soon as the latch is retracted.

11. In a switch of the class described, the combination of a supporting member, a blade pivotally mounted thereon and having a heel extending rearwardly of its pivot, a latch pivotally mounted on the supporting member and normally engaging under the heel of the blade, means automatically operable by a predetermined overload to retract said latch from beneath the blade, manually operable means for retracting the latch in a similar manner, each of said. means having a lost motion connection with the latch so that when one is operated to retract the latch the other will not be moved thereby, and means for opening the blade as soon as the latch is retracted.

l2. In a switch of the class described, the combination of a supporting member, a blade pivotally mounted thereon and having a heel extending rearwardly of its pivot, said supporting member having an armA extending beneath isaid heel and-spaced therefrom, a

latch pivoted to said arm and extending up` wardly past the heel of the blade and having a portion normally engaging underneath said 4heel to hold the blade closed, a solenoid secured to said supporting member and havl retracte ing a plunger pivotally connected to the latch above the heel of the blade, said solenoid having a coil through which the current normally passes and operable when subjected to a` predetermined overload to actuate the plunger and retract the latch from beneath the heel of the blade, and means for opening the blade as soon as the latch is retracted.

13. In a switch of the class. described, the

combination of a supporting member, a blade pivotally mounted thereon and having a heel latch pivoted to said arm and extending upwardly past the heel of the blade and havin a portion normally engaging underneath sai heel to hold the blade closed, a solenoid secured to said supporting member and having a plunger pivotally connected to the latch above the heel of the blade, said solenoid having a coil through which the current normally passes and which, when energized, tends to actuate the plunger to retract the latch from beneath the heel of the blade, spring means for resisting such retraction, means for-adjusting and gaging the tension of said s ring, means so that the latch will be when the solenoid is subjected to any predetermined overload, and means for` opening the blade as soon as the latch is retracted. v

14. In a switch of the class described, the combination of a supporting member, a blade pivotally mounted thereon and havin a heel extending rearwardly of its pivot, said supporting member having an arm extending eneath -said heel and spaced therefrom, a

latch pivoted to said arm and extending upwardly past the heel of the blade and having a portion normally engaging underneath said heel to hold the blade closed, a solenoid secured to said supporting member and hav- Ving a plunger pivotally connected to the latch above the heel of the blade, said solenoid having a coil through which the current normally passes and operable when subjected to a predetermined overload to ac-tuate theplunger and retract the latch from beneath the heel of the blade, means for opening the blade as soon as the latch is retracted, and means for establishing al short circuit past the coilas soon as the plunger has been so moved, whereby to prevent injury tothe coil in case the switch fails to open under such conditions.

15. In a switch of the class described,'the

Icombination of a supporting member, a blade pivotally mounted thereon and having a heel extending rearwardly of its pivot, sa1d. sup

ortin,l member having an arm extending beneath said heel and spaced therefrom, a latch pivoted to said arm 'and extending upwardly past the heel of the blade and-havin a portion normally enga mg underneath said heel to holdthe blade c osed, a solenoid secured to said supporting member and having a plunger plvotally connected to the latch above the heel of the blade, said solenoid having a coil through which the currentA normally passes and which, when energized,

tends to actuate'the plunger to retract the latch from beneath the heel of the blade, spring means for resisting such retraction, means for adjusting and gaging the tension of said spring means so that the latch will be retracted when the solenoid is subjected to any predetermined overload, means for opening the blade as soon as the latch is retracted, and means for establishing a short circuit past the coil as soon as the plunger 'has been actuated by said predetermined overload, whereby to prevent injury to the coil in case the switch fails to open under such conditions.

16. In a switch of the class described, the

`combination of a supporting member, a blade pivotally mounted thereon and having a heel extending rearwardly of its pivot, insulators on which the supporting member is mounted,

a latch pivotally mounted on the supporting member and normally engaging under the heel of the blade, means operable by a predetermined overload to retract said latch from beneath the blade, manually operated means for rocking one of said insulators about a central vertical axis, and a cam secured on the reckable insulator and having a surface engageable with the heel of the blade to close the latter when the insulator is rocked to a certain position. j

17. In a switch of the class described, the combination with a pivoted switch blade and 'jaws with which the same is adapted to contact, said blade having a-heel extending rearwardly of its pivot, ofl a cam mounted for rocking movement about a vertical axis and having a face engageable with the heel of the blade to closev the latter when the cam is rocked in one direction to a certain position, a' spring-held latch automatically engageable underneath said heel to maintain the blade in closed position after the cam is .rocked in the opposite' direction, and means automatically operable by a predetermined overload to retract said latch and'cause the switch blade to open.

18. In a switch of the class. described, the

combination with a pivoted switch blade and 'jaws With-which the same is adapted to contact, said blade having a heel extending rearwardly of lits pivot., of a cammounted for y rocking movement about a vertical axis and havingia face engageable with the heelv of the bladeA to close the latter. when the cam is rocked in one direction to-a certain position,

a sprin -held latch automatically' eng eable un erneathsaid heel tq maintain t e" blade in closed position after the cam is vrocked in the opposite direction, a solenoid having a, plunger connected to the latch, said solenoid having a coil through which the current normally passes and operable, when subjected to a predetermined overload, to actuate the plunger to retract the latch from beneath the heel of the blade, thereby causing the blade to open.

19. In a switch of the class described, the combination of a plurality of switch blades arranged in a gang, each unit of the gang including a pair of jaws with which the corresponding blade is adapted to contact, a'supporting member to which the blade is pivoted, and a pair of insulators on which the supporting member is mounted, one of said insulators being rockable about its axis, means operable automatically to cause any one of said blades to open when an excessive current passes therethrough, means operable by the opening of said blade to rock in unison all of the insulators which are lrockably mounted, and means actuated by the rocking movement of said insulators to open the other blades in the gang.

20. In a switch of the class described, the combination of a plurality of switch blades arranged in a gang, each unit of the gang including a pair oit-jaws with which the corresponding blade, is adapted to Contact, a supporting member on which the blade is pivoted, and a pair of insulators on which the supporting member is mounted, one of the insulators in each gang being mounted for rocking movement, each blade having a heel extending rearwardly from its pivot, a cam on each rockable insulator and engageable with the heel of the corresponding blade to close the same when the insulator is rocked in one direction to a certain position, a spring-held pivoted latch automatically enageable underneath said heel to hold the blade closed after the cam is rocked in the opposite direction, and means automatically operable by a predetermined overload through any one of the blades to retract the corresponding/latch and cause the blade to open. 21. In a switch of the class described, the

-combination of a plurality of switch blades auanged in a gang, each unit of the gang including a pair of jaws with which the corresponding blade is adapted to contact, a supporting member on which the blade is pivoted, and a pair of insulators on which the supporting member is mounted, one of the insulators in each gang being mounted for rocking movement, each blade having a heel extending rearwardly from its pivot, a cam on each rockable insulator and engageable with the heel of the corresponding bladeto close the same when the insulator is rocked in one direction to a certain position, a spring held latch automatically engageable underneath said heel to hold the blade closed after the cam is rocked in the opposite direction, a

,solenoid having a plunger connectedY to the latch, said solenoid having a coil through which the current normally passes, and operable whensubjccted to a predetermined overl" load to actuate the plunger to retract the latch from beneath the heel of the blade, thereby causing the blade to open.

22. In a switch of the class described, the combination of a plurality of switch blades arranged in a gang, each unit of the gang including a pair of jaws with which the corresponding blade is adapted to contact, a sup` porting member on which thev blade is pivoted, and a pair of insulators on which the supporting member is mounted,'one of the insulators in the gang being mounted to rock about a vertical axis, each blade having a heel extending rearwardly from its pivot, a cam on each rockabie insulator and engageable with the heel of the corresponding blade to close the same when the insulator is rocked in one direction to a certain position,a latch automatically engageable underneath the heel of the blade to hold it closed after the cam is rocked to a certain extent in a reverse direction, means operable by a predetermined overload passing through any one of the switch blades to retract the corresponding latch and cause the blade to open, each cam having a portion engageable by the heel of the corresponding blade, when opening, to rockthe cam further in a reverse direction, and means actuated thereby for opening the other switches in the gang.

23. In a switch of the class described the combination of a plurality of switch blades arranged in a gang, each unit of the gang including a pair of jaws with which the corre sponding blade is adapted to contact, a supporting member on which the blade is pivoted, and a pair of insulators on which the supporting member is mounted, one of the insulators in the gang being mounted to rock about a vertical axis, each blade having a heel extending rearwardly from its pivot, a cam on each rockable insulator and engageable with the heel of the corresponding blade to close the same when the insulator is rocked in one direction to a certain position, a latch automatically engageable underneath the heel 4of the blade to hold it closed after the cam is rocked to a certain extent in a reverse direction, ay solenoid mounted on each supporting member and having a plunger connected .to the corresponding latch', said solenoid having a coil through which the current normally passes and operable, when subjected to a predetermined overload, to actuate the plunger to retract the latch from beneath the heel of the blade, thereby causing the blade to open, each cam having a portion engageable by the heel of the corresponding blade, whenopening, to rock the cam further/'inv a reverse direction, and'means actuated thereby for causing the other switches in the gang to open.

24. In an automatic switch of the class described, the combination of a plurality of switch blades arranged in a gang, each unit of the gang including a pair of jaws with which the corresponding blade is adapted to contact, means operable b a predetermined current overload passing t irough any one of the blades to cause the same to open, and means vindependent of the solenoid mechalo nism engageable by a part of that blade in opening and actuated thereby to cause the other blades also to open.

25. In a switch of the class described, the combination of a plurality of switch blades arranged in a gang, each unit of the gaugin-l cludmg a pair of ]aws with whlch the cor' responding blade is adapted to contact, each blade having a rearwardly extending heel, a latch cooperating with the heel to hold the blade closed, means for automatically retracting the latch to cause the blade to open whenever the current is excessive, and means engageable b-y the heel of the blade in opening and'actuated thereby to release the other latches, thereby causing all of the other blades also to open.

end; solenoid operated latches cooperating with said heels to lock the blades closed; manually operable cams also cooperating with the heels connectedto close the blades in unison; and links connected to move the cams to trip the latches of the closed switches when one of the blades flies open and strikesits cam. f

In testimony, that I claim the foregoing as my own, I have hereto afIiXed my signature.

TOMLINSON F. JOHNSON, JR.

26. An automatic, air break, instantanel ous, overload switch having solenoid operated trip mechanism; and means automatically to short circuit the solenoid when the trip mechanism is actuated and before the switch breaks the circuit.

27. An air break. automatic, gang switch comprising, in combination, pivoted switch 4 blades each presenting a heel portion; and manually operable cam means cooperating with the heels to close all of the blades in unic `,son and movable to a position to permit all of the blades to fly open.

28. An air break automatic gang switch comprising, in comination, pivoted switch blades each presenting a heel portion; and 'v manually operable cams cooperating with'the heels to close all of the blades in unison and .45 movable to a position to permit all of the blades to fly open.

29. An air break automatic gang switch comprising, in combination, pivoted switch blades each presenting a heel portion; latch means cooperating with the heels to lock the blades closed; latch tripping means operablev responsive to predetermined current conditions; and manually operable means cooperating with the heels to close all of the blades in unison and movable to a position to permit all of the blades rto fly open.

30. An automatic, air break'overload gang switch comprising, in combination, pivoted, vertically swinging switch blades; solenoids e0 having plungers cooperating with latches to lock the blades closed and to be tripped automatically under predetermined current conditions; manually operable cams cooperating with the blades to close them and movable to positions to permit the blades to swing 

